Laser projecting device and light-combining lens

ABSTRACT

A laser projecting device and a light-combining lens are provided. The light-combining lens is a one-piece structure, and has a difference of refractive indexes less than 0.2. The light-combining lens includes collimation surfaces, reflection surfaces, and a light emergent surface. Each collimation surface defines a collimation path inside the light-combining lens. The reflection surfaces respectively located at the collimation paths are parallel to each other and arranged along an arrangement direction. The light emergent surface is located at the arrangement direction. Each reflection surface and the corresponding collimation path have an acute angle therebetween to define a reflection path. The reflection paths are overlapped in the light-combining lens to define a light-combining path. The light combining path passes through at least one of the reflection surfaces that allows light to pass therethrough along the light-combining path, and passes through the light-combining lens from the light emergent surface.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims priority to the U.S. Provisional PatentApplication Ser. No. 62/899,225 filed on Sep. 12, 2019, whichapplication is incorporated herein by reference in its entirety.

The present application is a divisional application of application Ser.No. 17/004,283, filed on Aug. 27, 2020 and entitled “LASER PROJECTINGDEVICE AND LIGHT-COMBINING LENS,” now allowed. Moreover, this divisionalapplication rejoins claims based on Species of FIG. 1 and FIG. 2 ,according to the Restriction Requirement dated Aug. 20, 2021, augmentedwith new claims supported by original specification.

Some references, which may include patents, patent applications andvarious publications, may be cited and discussed in the description ofthis disclosure. The citation and/or discussion of such references isprovided merely to clarify the description of the present disclosure andis not an admission that any such reference is “prior art” to thedisclosure described herein. All references cited and discussed in thisspecification are incorporated herein by reference in their entiretiesand to the same extent as if each reference was individuallyincorporated by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a lens, and more particularly to alaser projecting device and a light-combining lens.

BACKGROUND OF THE DISCLOSURE

A conventional light-combining assembly includes a plurality of opticalmembers spaced apart from each other and arranged in a chamber, andthere is air between any two of the optical members. As such, theconventional light-combining assembly has a large volume. Moreover, whenthe conventional light-combining assembly is used in a light-combiningprocess for combining lights, the lights would travel in an environmenthaving extremely different refractive indices, thereby causing theefficiency and the accuracy of the light-combining process to be easilyaffected.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacies, the presentdisclosure provides a laser projecting device and a light-combining lensto effectively improve on issues associated with conventionallight-combining assemblies.

In one aspect, the present disclosure provides a laser projectingdevice, which includes a light-combining lens and a laser module. Thelight-combining lens is formed as a one-piece structure and has adifference of refractive indexes therein that is less than 0.2. Thelight-combining lens includes a front portion, a rear portion, and anexpanding portion. The front portion includes a front collimationsurface and a front reflection surface. The front collimation surfacedefines a front collimation path inside of the front portion. The frontreflection surface is located at the front collimation path. The frontcollimation path and the front reflection surface have an acute angletherebetween and jointly define a front reflection path. The rearportion includes a rear collimation surface, a rear reflection surface,and a light emergent surface. The rear collimation surface defines arear collimation path inside of the rear portion. The rear reflectionsurface is located at the rear collimation path. The rear collimationpath and the rear reflection surface have an acute angle therebetweenand jointly define a rear reflection path. The rear reflection surfaceallows light to pass therethrough from one side of the rear reflectionsurface that is opposite to the rear reflection path. The light emergentsurface is arranged on a surface of the rear portion away from the frontreflection surface. The expanding portion is disposed between the frontportion and the rear portion along an arrangement direction. Theexpanding portion includes an expanding collimation surface and anexpanding reflection surface. The expanding collimation surface definesan expanding collimation path inside of the expanding portion. Theexpanding reflection surface is located at the expanding collimationpath. The expanding collimation path and the expanding reflectionsurface have an acute angle therebetween and jointly define an expandingreflection path. The expanding reflection surface allows light to passtherethrough from one side of the expanding reflection surface that isopposite to the expanding reflection path. The front reflection path,the expanding reflection path, and the rear reflection path areoverlapped with each other in the light-combining lens so as to jointlydefine a light-combining path that extends outside of thelight-combining lens from the light emergent surface. The laser modulecorresponds in position to the light-combining lens, and includes asubstrate and three laser emitters. The three laser emitters are mountedon the substrate and respectively face toward the front collimationsurface, the rear collimation surface, and the expanding collimationsurface. The three laser emitters are configured to respectively emitlights traveling along the front collimation path, the expandingcollimation path, the rear collimation path, and the light-combiningpath. The light-combining lens and each of the three laser emitters havea separation distance therebetween, the separation distancescorresponding to the three laser emitters are different from each other,and any one of the separation distances is smaller than a focal lengthof any one of the front collimation surface, the rear collimationsurface, and the expanding collimation surface.

In another aspect, the present disclosure provides a light-combininglens, which is formed as a one-piece structure and has a difference ofrefractive indexes therein that is less than 0.2. The light-combininglens includes a front portion and a rear portion. The front portionincludes a front collimation surface and a front reflection surface. Thefront collimation surface defines a front collimation path inside of thefront portion. The front reflection surface is located at the frontcollimation path. The front collimation path and the front reflectionsurface have an acute angle therebetween and jointly define a frontreflection path. The rear portion and the front portion are arrangedalong an arrangement direction, and the rear portion includes a rearcollimation surface, a rear reflection surface, and a light emergentsurface. The rear collimation surface defines a rear collimation pathinside of the rear portion. The rear reflection surface is located atthe rear collimation path. The rear collimation path and the rearreflection surface have an acute angle therebetween and jointly define arear reflection path. The rear reflection surface allows light to passtherethrough from one side of the rear reflection surface that isopposite to the rear reflection path. The light emergent surface isarranged on a surface of the rear portion away from the front reflectionsurface. The front reflection path and the rear reflection path areoverlapped with each other in the light-combining lens so as to jointlydefine a light-combining path that extends outside of thelight-combining lens from the light emergent surface.

In yet another aspect, the present disclosure provides a light-combininglens, which is formed as a one-piece structure and has a difference ofrefractive indexes therein that is less than 0.2. The light-combininglens includes a plurality of collimation surfaces, a plurality ofreflection surfaces, and a light emergent surface. Each of thecollimation surfaces defines a collimation path inside of thelight-combining lens. The reflection surfaces are respectively locatedat the collimation paths. The reflection surfaces are arranged along anarrangement direction and are parallel to each other. Each of thereflection surfaces and one of the collimation paths correspondingthereto have an acute angle therebetween and jointly define a reflectionpath. The reflection paths are overlapped with each other in thelight-combining lens so as to jointly define a light-combining path. Thelight-combining path passes through at least one of the reflectionsurfaces that allows light to pass therethrough by traveling along thelight-combining path. The light emergent surface is located at thearrangement direction. The light-combining path extends outside of thelight-combining lens from the light emergent surface.

Therefore, as the light-combining lens in the present disclosure is aone-piece structure and has a difference of refractive indexes thereinthat is less than 0.2, when the light-combining lens is applied to alight-combining process for combining lights, the lights would travel ina medium (i.e., the light-combining lens) having a difference ofrefractive indexes therein that is less than 0.2, thereby effectivelyincreasing the efficiency and the accuracy of the light-combiningprocess. Moreover, the light-combining lens that is formed as aone-piece structure is effectively reduced in its overall volume, and istherefore capable of being applied to the laser module that isminiaturized.

These and other aspects of the present disclosure will become apparentfrom the following description of the embodiment taken in conjunctionwith the following drawings and their captions, although variations andmodifications therein may be affected without departing from the spiritand scope of the novel concepts of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thefollowing detailed description and accompanying drawings.

FIG. 1 is a schematic view of a laser projecting device according to afirst embodiment of the present disclosure.

FIG. 2 is a schematic view of a light-combining lens of the laserprojecting device according to the first embodiment of the presentdisclosure.

FIG. 3 is a schematic view of a laser projecting device according to asecond embodiment of the present disclosure.

FIG. 4 is a schematic view of a light-combining lens of the laserprojecting device according to the second embodiment of the presentdisclosure.

FIG. 5 is a schematic view of a laser projecting device according to athird embodiment of the present disclosure.

FIG. 6 is a schematic view of a light-combining lens of the laserprojecting device according to the third embodiment of the presentdisclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present disclosure is more particularly described in the followingexamples that are intended as illustrative only since numerousmodifications and variations therein will be apparent to those skilledin the art. Like numbers in the drawings indicate like componentsthroughout the views. As used in the description herein and throughoutthe claims that follow, unless the context clearly dictates otherwise,the meaning of “a”, “an”, and “the” includes plural reference, and themeaning of “in” includes “in” and “on”. Titles or subtitles can be usedherein for the convenience of a reader, which shall have no influence onthe scope of the present disclosure.

The terms used herein generally have their ordinary meanings in the art.In the case of conflict, the present document, including any definitionsgiven herein, will prevail. The same thing can be expressed in more thanone way. Alternative language and synonyms can be used for any term(s)discussed herein, and no special significance is to be placed uponwhether a term is elaborated or discussed herein. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termsis illustrative only, and in no way limits the scope and meaning of thepresent disclosure or of any exemplified term. Likewise, the presentdisclosure is not limited to various embodiments given herein. Numberingterms such as “first”, “second” or “third” can be used to describevarious components, signals or the like, which are for distinguishingone component/signal from another one only, and are not intended to, norshould be construed to impose any substantive limitations on thecomponents, signals or the like.

First Embodiment

Referring to FIG. 1 and FIG. 2 , a first embodiment of the presentdisclosure provides a laser projecting device 1000 that can be appliedto a laser beam scanning (LBS) apparatus, but the present disclosure isnot limited thereto. The laser projecting device 1000 includes alight-combining lens 100 and a laser module 200 that corresponds inposition to the light-combining lens 100.

It should be noted that the light-combining lens 100 in the presentembodiment is described in cooperation with the laser module 200, butthe present disclosure is not limited thereto. For example, in otherembodiments of the present disclosure, the light-combining lens 100 canbe independently used (e.g., sold) or can be used in cooperation withother components (e.g., any light emitting module other than the lasermodule 200). The following description describes the structure andconnection relationship of each of the light-combining lens 100 and thelaser module 200.

The light-combining lens 100 is formed as a one-piece structure and hasa difference of refractive indexes therein that is less than 0.2. Inother words, any light-combining assembly including optical membersspaced apart from each other by air is different from thelight-combining lens 100 of the present embodiment. Or, anylight-combining assembly having a difference of refractive indexes morethan 0.2 is different from the light-combining lens 100 of the presentembodiment.

The light-combining lens 100 in the present embodiment includes a frontportion 1, at least one expanding portion 2, a rear portion 3, and anoptical colloid 4. The front portion 1, the at least one expandingportion 2, and the rear portion 3 are arranged along an arrangementdirection D1. In other words, the at least one expanding portion 2 isdisposed between the front portion 1 and the rear portion 3.

Moreover, the quantity of the at least one expanding portion 2 in thepresent embodiment is one, but the present disclosure is not limitedthereto. For example, in other embodiments of the present disclosure,the light-combining lens 100 can be provided without the expandingportion 2 and/or the optical colloid 4; or, the quantity of the at leastone expanding portion 2 can be more than one.

The front portion 1, the expanding portion 2, and the rear portion 3 inthe present embodiment are made of the same material (e.g., a glass oran optical plastic), and are integrally connected to each other so as tobe formed as a one-piece structure. For example, the front portion 1,the expanding portion 2, and the rear portion 3 can be formed bydirectly processing a piece of glass or optical plastic, therebyeffectively reducing a tolerance in a combining process of the frontportion 1, the expanding portion 2, and the rear portion 3, but thepresent disclosure is not limited thereto. The front portion 1, theexpanding portion 2, and the rear portion 3 have a same refractive indexthat is defined as a first refractive index, and the optical colloid 4has a second refractive index. Moreover, a difference between the firstrefractive index and the second refractive index is less than 0.2.

Furthermore, in order to clearly describe the structure of thelight-combining lens 100, the following description describes thestructure of each of the front portion 1, the expanding portion 2, andthe rear portion 3, and then describes the connection relationship ofthe front portion 1, the expanding portion 2, and the rear portion 3.

In the present embodiment, (an outer surface of) the front portion 1includes a front collimation surface 11 and a front reflection surface12. The front collimation surface 11 in the present embodiment is aconvex surface and defines a front collimation path P1 a inside of thefront portion 1. The front reflection surface 12 is located at the frontcollimation path P1 a, and the front collimation path P1 a and the frontreflection surface 12 have a first acute angle therebetween and jointlydefine a front reflection path P1 b.

Specifically, the front collimation surface 11 can be used to guidelight outside of the light-combining lens 100 to travel toward the frontreflection surface 12 by penetrating into the front portion 1 along thefront collimation path P1 a, such that the light can travel along thefront reflection path P1 b by being reflected from the front reflectionsurface 12. Moreover, the front reflection surface 12 does not allow anylight to pass therethrough from one side of the front reflection surface12 (e.g., a left side of the front reflection surface 12 shown in FIG. 2) that is opposite to the front reflection path P1 b.

In the present embodiment, (an outer surface of) the expanding portion 2includes an expanding collimation surface 21 and an expanding reflectionsurface 22. The expanding collimation surface 21 in the presentembodiment is a convex surface and defines an expanding collimation pathP2 a inside of the expanding portion 2. The expanding reflection surface22 is located at the expanding collimation path P2 a, and the expandingcollimation path P2 a and the expanding reflection surface 22 have asecond acute angle therebetween and jointly define an expandingreflection path P2 b.

Specifically, the expanding collimation surface 21 can be used to guidelight outside of the light-combining lens 100 to travel toward theexpanding reflection surface 22 by penetrating into the expandingportion 2 along the expanding collimation path P2 a, such that the lightcan travel along the expanding reflection path P2 b by being reflectedfrom the expanding reflection surface 22. Moreover, the expandingreflection surface 22 allows light to pass therethrough from one side ofthe expanding reflection surface 22 (e.g., a left side of the expandingreflection surface 22 shown in FIG. 2 ) that is opposite to theexpanding reflection path P2 b. In other words, the light that travelsalong the front reflection path P1 b, after passing through the frontportion 1, can pass through the expanding reflection surface 22 totravel along the expanding reflection path P2 b.

In the present embodiment, (an outer surface of) the rear portion 3includes a rear collimation surface 31, a rear reflection surface 32,and a light emergent surface 33. The rear collimation surface 31 in thepresent embodiment is a convex surface and defines a rear collimationpath P3 a inside of the rear portion 3. The rear reflection surface 32is located at the rear collimation path P3 a, and the rear collimationpath P3 a and the rear reflection surface 32 have a third acute angletherebetween and jointly define a rear reflection path P3 b. The lightemergent surface 33 is arranged on a surface of the rear portion 3 awayfrom the front reflection surface 12.

Specifically, the rear collimation surface 31 can be used to guide lightoutside of the light-combining lens 100 to travel toward the rearreflection surface 32 by penetrating into the rear portion 3 along therear collimation path P3 a, such that the light can travel along therear reflection path P3 b by being reflected from the rear reflectionsurface 32. Moreover, the rear reflection surface 32 allows light topass therethrough from one side of the rear reflection surface 32 (e.g.,a left side of the rear reflection surface 32 shown in FIG. 2 ) that isopposite to the rear reflection path P3 b. In other words, the lightthat travels along the front reflection path P1 b and the expandingreflection surface P2 b, after passing through the expanding portion 2,can pass through the rear reflection surface 32 to travel along the rearreflection path P3 b.

The above description describes the structure of each of the frontportion 1, the expanding portion 2, and the rear portion 3, and thefollowing description describes the connection relationship of the frontportion 1, the expanding portion 2, and the rear portion 3.

The front collimation surface 11, the expanding collimation surface 21,and the rear collimation surface 31 in the present embodiment have asame focal length, and the focal length of any one of the frontcollimation surface 11, the expanding collimation surface 21, and therear collimation surface 31 is preferably within a range of 1.7 mm to4.5 mm, but the present disclosure is not limited thereto. For example,in other embodiments of the present disclosure, any two of the frontcollimation surface 11, the expanding collimation surface 21, and therear collimation surface 31 can have different focal lengths.

Moreover, the front collimation surface 11, the expanding collimationsurface 21, and the rear collimation surface 31 in the presentembodiment have a same tangent plane. In other words, any two of thefront collimation surface 11, the expanding collimation surface 21, andthe rear collimation surface 31 do not have any step difference in anincident direction D2 perpendicular to the arrangement direction D1.

The front reflection surface 12, the expanding reflection surface 22,and the rear reflection surface 32 are arranged in one row along thearrangement direction D1 and are parallel to each other. The first acuteangle, the second acute angle, and the third acute angle in the presentembodiment have the same value (e.g., 45 degrees) that can be adjustedor changed according to design requirements, and the present disclosureis not limited thereto. For example, in other embodiments of the presentdisclosure, the first acute angle, the second acute angle, and the thirdacute angle can be of different values.

Specifically, the front reflection path P1 b, the expanding reflectionpath P2 b, and the rear reflection path P3 b are overlapped with eachother in the light-combining lens 100 (i.e., the expanding reflectionpath P2 b defined by the at least one expanding portion 2 is overlappedwith the front reflection path P1 b and the rear reflection path P3 b)so as to jointly define a light-combining path P0 that extends outsideof the light-combining lens 100 from the light emergent surface 33.

In other embodiments of the present disclosure that do not include theexpanding portion 2, the front reflection path P1 b and the rearreflection path P3 b are overlapped with each other in thelight-combining lens 100, so as to jointly define the light-combiningpath P0 that extends outside of the light-combining lens 100 from thelight emergent surface 33.

Moreover, in the light-combining lens 100 of the present embodiment,parts of the front collimation surface 11, the expanding collimationsurface 21, and the rear collimation surface 31 adjacent to each otherare connected to each other, so that the front portion 1, the expandingportion 2, and the rear portion 3 can have a plurality of slots Sarranged in regions thereof through which the light-combining path P0passes, but the present disclosure is not limited thereto.

For example, in other embodiments of the present disclosure, aperipheral part of the front collimation surface 11 can be connected toa peripheral part of the expanding reflection surface 22, and aperipheral part of the expanding collimation surface 21 can be connectedto a peripheral part of the rear reflection surface 32, so that any twoof the front collimation surface 11, the expanding collimation surface21, and the rear collimation surface 31 have a step differencetherebetween.

In addition, the optical colloid 4 in the present embodiment is filledin the slots S, and the light-combining path P0 is located in the frontportion 1, the expanding portion 2, the rear portion 3, and the opticalcolloid 4. Accordingly, when the light-combining lens 100 is applied toa light-combining process for combining lights, the lights would travelin a medium (i.e., the light-combining lens 100) having a difference ofrefractive indexes therein that is less than 0.2, thereby effectivelyincreasing the efficiency and the accuracy of the light-combiningprocess.

It should be noted that the terms “front” and “rear” used in names ofthe corresponding components of the present embodiment are defined bythe sequence of the light-combining process along the light-combiningpath P0, so as to distinguish different portions of the light-combininglens 100 from each other. The terms “front” and “rear” are not used tolimit the relative position of the corresponding components.

In other words, (an outer surface of) the light-combining lens 100includes a plurality of collimation surfaces 11, 21, 31, a plurality ofreflection surfaces 12, 22, 32, and a light emergent surface 33. Each ofthe collimation surfaces 11, 21, 31 defines a collimation path P1 a, P2a, P3 a inside of the light-combining lens 100. The reflection surfaces12, 22, 32 are respectively located at the collimation paths P1 a, P2 a,P3 a. The reflection surfaces 12, 22, 32 are arranged along anarrangement direction D1 and are parallel to each other. Each of thereflection surfaces 12, 22, 32 and the corresponding collimation path P1a, P2 a, P3 a have an acute angle therebetween and jointly define areflection path P1 b, P2 b, P3 b. The light emergent surface 33 islocated at the arrangement direction D1.

Moreover, the reflection paths P1 b, P2 b, P3 b defined by thereflection surfaces 12, 22, 32 are overlapped with each other in thelight-combining lens 100 so as to jointly define a light-combining pathP0. The light-combining path P0 passes through two of the reflectionsurfaces 22, 32 that allow light to pass therethrough by traveling alongthe light-combining path P0, and the light-combining path P0 extendsoutside of the light-combining lens 100 from the light emergent surface33.

The above description describes the structure of the light-combininglens 100. The following description describes the structure of the lasermodule 200, and the connection relationship between the laser module 200and the light-combining lens 100, but the present disclosure is notlimited thereto.

The laser module 200 includes a substrate 201, three laser emitters 202mounted on the substrate 201, and a fixing mechanism 203. Each of thethree laser emitters 202 has a light emitting surface 2021, and thethree laser emitters 202 in the present embodiment are configured toemit lights having different colors (e.g., a red laser light, a greenlaser light, and a blue laser light), but the present disclosure is notlimited thereto. In addition, the reflection surfaces 12, 22, 32 in thepresent embodiment can be optically coating films that are respectivelycapable of reflecting the lights emitted from the three laser emitters202, but the present disclosure is not limited thereto. For example, inother embodiments of the present disclosure, each of the reflectionsurfaces 12, 22, 32 can be formed on the corresponding positions of thelight-combining lens 100 in an adhering manner or a grinding manner.

Moreover, any two of the light emitting surfaces 2021 have a stepdifference therebetween in the incident direction D2, and (the lightemitting surfaces 2021 of) the three laser emitters 202 respectivelyface toward the front collimation surface 11, the expanding collimationsurface 21, and the rear collimation surface 31. The light-combininglens 100 and each of the three laser emitters 202 have a separationdistance therebetween, the separation distances corresponding to thethree laser emitters 202 are different from each other, and any one ofthe separation distances is smaller than the focal length of any one ofthe front collimation surface 11, the expanding collimation surface 21,and the rear collimation surface 31.

In the present embodiment, the laser emitter 202 configured to emit thered laser light faces toward the front collimation surface 11 andcorresponds to a smallest one of the separation distances, and the laseremitter 202 configured to emit the blue laser light faces toward therear collimation surface 31 and corresponds to a largest one of theseparation distances, but the present disclosure is not limited thereto.For example, in other embodiments of the present disclosure, thepositions of the three laser emitters 202 can be changed according todesign requirements.

Specifically, the structural design of the light-combining lens 100 inthe present embodiment can be applied to the laser module 200 that isminiaturized. For example, a distance between any two of the lightemitting surfaces 2021 adjacent to each other is preferably less than orequal to 50% of the focal length of any one of the front collimationsurface 11, the expanding collimation surface 21, and the rearcollimation surface 31, but the present disclosure is not limitedthereto.

Moreover, the lights emitted from the three laser emitters 202 cantravel along the front collimation path P1 a, the expanding collimationpath P2 a, the rear collimation path P3 a, and the light-combining pathP0, and then the lights would travel out of the light-combining lens 100by passing through the light emergent surface 33 so as to be combined toform a light beam. In the present embodiment, the light-combining lens100 allows the lights emitted from the three laser emitters 202 to becompletely overlapped with each other, when the lights travel along thelight-combining path P0 to pass through the light emergent surface 33,but the present disclosure is not limited thereto.

In addition, the relative position of the light-combining lens 100 andthe three laser emitters 202 can be adjusted in more than one dimensionaccording to design requirements, and then the fixing mechanism 203(e.g., an adhesive mechanism, a screwing mechanism, or an engagingmechanism) would be used to maintain the relative position of thelight-combining lens 100 and the three laser emitters 202.

Second Embodiment

Referring to FIG. 3 and FIG. 4 , a second embodiment of the presentdisclosure is similar to the first embodiment of the present disclosure.For the sake of brevity, descriptions of the same components in thefirst and second embodiments of the present disclosure will be omittedherein, and the following description only discloses different featuresbetween the first and second embodiments.

In the present embodiment, the light-combining lens 100 does not includethe optical colloid 4 of the first embodiment, and is not formed withthe slots S of the first embodiment. Furthermore, the light-combininglens 100 in the present embodiment includes two optical adhesive layers5. The front portion 1, the expanding portion 2, and the rear portion 3in the present embodiment are made of the same material (e.g., a glassor an optical plastic), and are adhered to each other through the twooptical adhesive layers 5 so as to formed a one-piece structure, but thepresent disclosure is not limited thereto.

Specifically, the front portion 1 has a front combination surface 13adjacent to the expanding reflection surface 22 (and substantiallyparallel to the front reflection surface 12), and the front combinationsurface 13 is gaplessly connected to the expanding reflection surface 22through one of the two optical adhesive layers 5. Furthermore, theexpanding portion 2 has an expanding combination surface 23 adjacent tothe rear reflection surface 32 (and substantially parallel to theexpanding reflection surface 22), and the expanding combination surface23 is gaplessly connected to the rear reflection surface 32 throughanother one of the two optical adhesive layers 5.

Moreover, a thickness of any one of the two optical adhesive layers 5 isless than or equal to 20 μm, and any one of the two optical adhesivelayers 5 in the present embodiment can have a nanoscale thickness, butthe present disclosure is not limited thereto. Each of the two opticaladhesive layers 5 has a second refractive index, and a differencebetween the first refractive index and the second refractive index isless than 0.2. Accordingly, when the light-combining lens 100 is appliedto a light-combining process for combining lights, the lights wouldtravel in a medium (i.e., the light-combining lens 100) having adifference of refractive indexes therein that is less than 0.2, therebyeffectively increasing the efficiency and the accuracy of thelight-combining process. Furthermore, the thickness of each of the twooptical adhesive layers 5 is extremely thin, so that a proportion of thetwo optical adhesive layers 5 in the light-combining path P0 isextremely low (e.g., being less than 1%). Accordingly, the two opticaladhesive layers 5 almost cannot affect the lights in the light-combiningprocess, thereby further increasing the efficiency and the accuracy ofthe light-combining process.

Third Embodiment

Referring to FIG. 5 and FIG. 6 , a third embodiment of the presentdisclosure is similar to the second embodiment of the presentdisclosure. For the sake of brevity, descriptions of the same componentsin the second and third embodiments of the present disclosure will beomitted herein, and the following description only discloses differentfeatures between the second and third embodiments.

In the present embodiment, the light emitting surfaces 2021 of the threelaser emitters 202 are coplanar with each other, and any two of thefront collimation surface 11, the expanding collimation surface 21, andthe rear collimation surface 31 have a step difference G therebetween inthe incident direction D2. Specifically, since lights emitted from thethree emitters 202 have different wavelengths, the front collimationsurface 11, the expanding collimation surface 21, and the rearcollimation surface 31 need to be respectively spaced apart from thelight emitting surfaces 2021 by different separation distances. However,it is difficult to control, as in the second embodiment, the differentseparation distances by adjusting the light emitting surfaces 2021.Accordingly, the different separation distances of the laser projectingdevice 1000 in the present embodiment are controlled by the lightemitting surfaces 2021 being coplanar with each other and thelight-combining lens 100 having the step differences G, so as tofacilitate the manufacturing of the laser projecting device 1000.

In conclusion, as the light-combining lens in the present disclosure isa one-piece structure and has a difference of refractive indexes thereinthat is less than 0.2, when the light-combining lens is applied to alight-combining process for combining lights, the lights would travel ina medium (i.e., the light-combining lens) having a difference ofrefractive indexes therein that is less than 0.2, thereby effectivelyincreasing the efficiency and the accuracy of the light-combiningprocess. Moreover, the light-combining lens that is formed as aone-piece structure is effectively reduced in its overall volume, and istherefore capable of being applied to the laser module that isminiaturized.

Moreover, the light-combining lens in the present disclosure can beeffectively formed as a one-piece structure having the difference ofrefractive indexes less than 0.2 by using the optical colloid or theoptical adhesive layers to cooperate with the front portion, theexpanding portion, and the rear portion, and to cooperate with thestructural design of the light-combining lens (e.g., the optical colloidbeing filled in the slots defined by the front portion, the expandingportion, and the rear portion that are integrally connected to eachother; or, the front portion, the expanding portion, and the rearportion being gaplessly connected to each other through the two opticaladhesive layers).

Specifically, the thickness of each of the two optical adhesive layersin the present disclosure is extremely thin, so that a proportion of thetwo optical adhesive layers in the light-combining path is extremely low(e.g., being less than 1%). Accordingly, the two optical adhesive layersalmost cannot affect the lights in the light-combining process, therebyfurther increasing the efficiency and the accuracy of thelight-combining process.

The foregoing description of the exemplary embodiments of the disclosurehas been presented only for the purposes of illustration and descriptionand is not intended to be exhaustive or to limit the disclosure to theprecise forms disclosed. Many modifications and variations are possiblein light of the above teaching.

The embodiments were chosen and described in order to explain theprinciples of the disclosure and their practical application so as toenable others skilled in the art to utilize the disclosure and variousembodiments and with various modifications as are suited to theparticular use contemplated. Alternative embodiments will becomeapparent to those skilled in the art to which the present disclosurepertains without departing from its spirit and scope.

What is claimed is:
 1. A laser projecting device comprising: alight-combining lens formed as a one-piece structure and having adifference of refractive indexes therein that is less than 0.2, whereinthe light-combining lens includes: a front portion including: a frontcollimation surface defining a front collimation path inside of thefront portion; and a front reflection surface located at the frontcollimation path, wherein the front collimation path and the frontreflection surface have a first acute angle therebetween and jointlydefine a front reflection path; a rear portion including: a rearcollimation surface defining a rear collimation path inside of the rearportion; a rear reflection surface located at the rear collimation path,wherein the rear collimation path and the rear reflection surface have asecond acute angle therebetween and jointly define a rear reflectionpath, and wherein the rear reflection surface allows light to passtherethrough from one side of the rear reflection surface that isopposite to the rear reflection path; and a light emergent surfacearranged on a surface of the rear portion away from the front reflectionsurface; and an expanding portion disposed between the front portion andthe rear portion along an arrangement direction, wherein the expandingportion includes: an expanding collimation surface defining an expandingcollimation path inside of the expanding portion; and an expandingreflection surface located at the expanding collimation path, whereinthe expanding collimation path and the expanding reflection surface havea third acute angle therebetween and jointly define an expandingreflection path, and wherein the expanding reflection surface allowslight to pass therethrough from one side of the expanding reflectionsurface that is opposite to the expanding reflection path; wherein thefront reflection path, the expanding reflection path, and the rearreflection path are overlapped with each other in the light-combininglens so as to jointly define a light-combining path that extends outsideof the light-combining lens from the light emergent surface; and a lasermodule corresponding in position to the light-combining lens andincluding: a substrate; and three laser emitters mounted on thesubstrate and respectively facing toward the front collimation surface,the rear collimation surface, and the expanding collimation surface,wherein the three laser emitters are configured to respectively emitlights traveling along the front collimation path, the expandingcollimation path, the rear collimation path, and the light-combiningpath; wherein the light-combining lens and each of the three laseremitters have a separation distance therebetween, the separationdistances corresponding to the three laser emitters are different fromeach other, and any one of the separation distances is smaller than afocal length of any one of the front collimation surface, the rearcollimation surface, and the expanding collimation surface; wherein thefront portion and the rear portion have a first refractive index,wherein at least one slot is formed in a region of the light-combininglens between the rear reflection surface and the front portion, whereinthe at least one slot has two non-parallel surfaces and is filled withan optical colloid having a second refractive index different than thefirst refractive index, and wherein the light-combing path goes throughthe optical colloid in the at least one slot.
 2. The laser projectingdevice according to claim 1, wherein the front portion, the rearportion, and the expanding portion are integrally connected to eachother so as to be formed as a one-piece structure, and a quantity of theat least one slot is more than one, wherein any two of the frontportion, the rear portion, and the expanding portion have one of theslots arranged in a region thereof through which the light-combiningpath passes, and wherein the slots are filled with the optical colloid.3. The laser projecting device according to claim 2, wherein theexpanding portion have the first refractive index, and a differencebetween the first refractive index and the second refractive index isless than 0.2.
 4. The laser projecting device according to claim 1,wherein the front reflection surface does not allow any light to passtherethrough from one side of the front reflection surface that isopposite to the front reflection path, and wherein the front reflectionsurface, the expanding reflection surface, and the rear reflectionsurface are arranged in one row along the arrangement direction and areparallel to each other.
 5. The laser projecting device according toclaim 1, wherein the focal length of any one of the front collimationsurface, the rear collimation surface, and the expanding collimationsurface is within a range of 1.7 mm to 4.5 mm.
 6. The laser projectingdevice according to claim 1, wherein the light-combining lens allows thelights emitted from the three laser emitters to be completely overlappedwith each other when the lights travel along the light-combining path topass through the light emergent surface.
 7. The laser projecting deviceaccording to claim 1, wherein each of the front collimation surface, theexpanding collimation surface, and the rear collimation surface is aconvex surface.
 8. The laser projecting device according to claim 1,wherein any two of the front collimation surface, the expandingcollimation surface, and the rear collimation surface do not have anystep difference in an incident direction perpendicular to thearrangement direction.
 9. The laser projecting device according to claim1, wherein the first acute angle, the second acute angle, and the thirdacute angle have a same value.
 10. A light-combining lens formed as aone-piece structure and having a difference of refractive indexestherein that is less than 0.2, the light-combining lens comprising: afront portion including: a front collimation surface defining a frontcollimation path inside of the front portion; and a front reflectionsurface located at the front collimation path, wherein the frontcollimation path and the front reflection surface have a first acuteangle therebetween and jointly define a front reflection path; and arear portion, wherein the rear portion and the front portion arearranged along an arrangement direction, and the rear portion includes:a rear collimation surface defining a rear collimation path inside ofthe rear portion; a rear reflection surface located at the rearcollimation path, wherein the rear collimation path and the rearreflection surface have a second acute angle therebetween and jointlydefine a rear reflection path, and wherein the rear reflection surfaceallows light to pass therethrough from one side of the rear reflectionsurface that is opposite to the rear reflection path; and a lightemergent surface arranged on a surface of the rear portion away from thefront reflection surface; wherein the front reflection path and the rearreflection path are overlapped with each other in the light-combininglens so as to jointly define a light-combining path that extends outsideof the light-combining lens from the light emergent surface; wherein thefront portion and the rear portion have a first refractive index,wherein at least one slot is formed in a region of the light-combininglens between the rear reflection surface and the front portion, whereinthe at least one slot has two non-parallel surfaces and is filled withan optical colloid having a second refractive index different than thefirst refractive index, and wherein the light-combing path goes throughthe optical colloid in the at least one slot.
 11. The light-combininglens according to claim 10, further comprising at least one expandingportion disposed between the front portion and the rear portion alongthe arrangement direction, wherein the at least one expanding portionincludes: an expanding collimation surface defining an expandingcollimation path inside of the expanding portion; and an expandingreflection surface located at the expanding collimation path, whereinthe expanding collimation path and the expanding reflection surface havea third acute angle therebetween and jointly define an expandingreflection path, and wherein the expanding reflection surface allowslight to pass therethrough from one side of the expanding reflectionsurface that is opposite to the expanding reflection path; wherein theexpanding reflection path defined by the at least one expanding portionis overlapped with the front reflection path and the rear reflectionpath so as to jointly define the light-combining path.
 12. Thelight-combining lens according to claim 11, wherein the front portion,the rear portion, and the at least one expanding portion are integrallyconnected to each other so as to be formed as a one-piece structure, anda quantity of the at least one slot is more than one, wherein any two ofthe front portion, the rear portion, and the at least one expandingportion adjacent to each other have one of the slots arranged in aregion thereof through which the light-combining path passes, andwherein the slots are filled with the optical colloid.
 13. Thelight-combining lens according to claim 11, wherein each of the frontcollimation surface, the expanding collimation surface, and the rearcollimation surface is a convex surface.
 14. The light-combining lensaccording to claim 11, wherein any two of the front collimation surface,the expanding collimation surface, and the rear collimation surface donot have any step difference in an incident direction perpendicular tothe arrangement direction.
 15. The light-combining lens according toclaim 11, wherein the first acute angle, the second acute angle, and thethird acute angle have a same value.
 16. The light-combining lensaccording to claim 10, wherein the front collimation surface and therear collimation surface have a same focal length that is within a rangeof 1.7 mm to 4.5 mm.
 17. A light-combining lens formed as a one-piecestructure and having a difference of refractive indexes therein that isless than 0.2, the light-combining lens comprising: a plurality ofcollimation surfaces each defining a collimation path inside of thelight-combining lens; a plurality of reflection surfaces respectivelylocated at the collimation paths, wherein the reflection surfaces arearranged along an arrangement direction and are parallel to each other,wherein each of the reflection surfaces and one of the collimation pathscorresponding thereto have an acute angle therebetween and jointlydefine a reflection path, wherein the reflection paths defined by thereflection surfaces are overlapped with each other in thelight-combining lens so as to jointly define a light-combining path, andwherein the light-combining path passes through at least one of thereflection surfaces that allows light to pass therethrough by travelingalong the light-combining path; and a light emergent surface located atthe arrangement direction, wherein the light-combining path extendsoutside of the light-combining lens from the light emergent surface;wherein the collimation surfaces, the reflection surfaces, and the lightemergent surface are arranged on at least two portions of thelight-combining lens that have a first refractive index, wherein atleast one slot is formed in a region of the light-combining lens betweenthe at least two portions, wherein the at least one slot has twonon-parallel surfaces and is filled with an optical colloid having asecond refractive index different than the first refractive index, andwherein the light-combing path goes through the optical colloid in theat least one slot.
 18. The light-combining lens according to claim 17,wherein the collimation surfaces have a same focal length that is withina range of 1.7 mm to 4.5 mm.
 19. The light-combining lens according toclaim 17, wherein any two of the collimation surfaces do not have anystep difference in an incident direction perpendicular to thearrangement direction.
 20. The light-combining lens according to claim17, wherein each of the collimation surfaces is a convex surface.